U.S. patent number 10,632,742 [Application Number 16/349,688] was granted by the patent office on 2020-04-28 for nozzle sensor evaluation.
This patent grant is currently assigned to Hewlett-Packard Development Company, L.P.. The grantee listed for this patent is HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.. Invention is credited to Daryl E Anderson, James Michael Gardner, Eric Martin.
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United States Patent |
10,632,742 |
Anderson , et al. |
April 28, 2020 |
Nozzle sensor evaluation
Abstract
A fluid ejection die including a plurality of drive bubble
devices, a sensor operatively connected to each drive bubble
device, and a current source connected to each sensor. Furthermore,
the fluid ejection die may include an evaluation logic connected to
each sensor and an impedance element. The evaluation logic can be
configured to selectively connect the current source, through the
impedance element, to the sensor.
Inventors: |
Anderson; Daryl E (Corvallis,
OR), Martin; Eric (Corvallis, OR), Gardner; James
Michael (Corvallis, OR) |
Applicant: |
Name |
City |
State |
Country |
Type |
HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P. |
Spring |
TX |
US |
|
|
Assignee: |
Hewlett-Packard Development
Company, L.P. (Spring, TX)
|
Family
ID: |
63252908 |
Appl.
No.: |
16/349,688 |
Filed: |
February 27, 2017 |
PCT
Filed: |
February 27, 2017 |
PCT No.: |
PCT/US2017/019777 |
371(c)(1),(2),(4) Date: |
May 14, 2019 |
PCT
Pub. No.: |
WO2018/156171 |
PCT
Pub. Date: |
August 30, 2018 |
Prior Publication Data
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|
|
|
Document
Identifier |
Publication Date |
|
US 20190366707 A1 |
Dec 5, 2019 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B41J
2/0458 (20130101); B41J 2/14153 (20130101); B41J
2/04541 (20130101) |
Current International
Class: |
B41J
2/045 (20060101); B41J 2/14 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2662724 |
|
Apr 2008 |
|
CA |
|
187483 |
|
Feb 2013 |
|
SG |
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WO-200061372 |
|
Oct 2000 |
|
WO |
|
WO-2016175740 |
|
Nov 2016 |
|
WO |
|
Primary Examiner: Polk; Sharon A.
Attorney, Agent or Firm: Mahamedi Paradice LLP
Claims
What is claimed is:
1. A fluid ejection die comprising: a plurality of drive bubble
devices; a sensor operatively connected to each drive bubble device
of the plurality of drive bubble devices; a current source
connected to each sensor; and an evaluation logic connected to each
sensor, each evaluation logic comprising an impedance element, each
evaluation logic configured to selectively connect the current
source through the impedance element to each sensor.
2. The fluid ejection die of claim 1, wherein the evaluation logic,
further comprises a capacitance device connected to the impedance
element in parallel.
3. The fluid ejection die of claim 1, wherein the evaluation logic
comprises: a first switch to selectively connect the current source
to ground; and a second switch to selectively connect the current
source through the impedance element to the sensor.
4. The fluid ejection die of claim 3, wherein the evaluation logic
further comprises: a third switch connected to the second switch
and the sensor; and a fourth switch connected to the third switch
and the impedance element.
5. The fluid ejection die of claim 4, wherein the evaluation logic
can selectively connect the current source through the impedance
element to the sensor by: opening the first switch; closing the
second switch; closing the third switch; and closing the fourth
switch to detect one or more voltage responses, and based on the
one or more voltage responses, determine a state of operability of
the current source.
6. The fluid ejection die of claim 4, wherein the evaluation logic
can selectively connect the current source through the impedance
element to the sensor by: opening the second switch; closing the
fourth switch; closing the third switch; and opening the first
switch, to detect one or more voltage responses and based on the
detected one or more voltage responses, determine a state of
operability of the third switch.
7. The fluid ejection die of claim 6, wherein the evaluation logic
simultaneously closes the third switch and opens the first switch
after closing the fourth switch.
8. The fluid ejection die of claim 1, wherein the impedance element
is at least one of a resistor, transistor, diode, or any
combination thereof.
9. A printer die comprising: a plurality of drive bubble devices; a
sensor operatively connected to each drive bubble device of the
plurality of drive bubble devices; a current source connected to
each sensor; and an evaluation logic connected to each sensor, each
evaluation logic comprising an impedance element, each evaluation
logic configured to selectively connect the current source through
the impedance element to each sensor.
10. The printer die of claim 9, wherein the evaluation logic,
further comprises a capacitance device connected to the impedance
element in parallel.
11. The printer die of claim 9, wherein the evaluation logic
comprises: a first switch to selectively connect the current source
to ground; and a second switch to selectively connect the current
source through the impedance element to the sensor.
12. The printer die of claim 11, wherein the evaluation logic
further comprises: a third switch connected to the second switch
and the sensor; and a fourth switch connected to the third switch
and the impedance element.
13. The printer die of claim 12, wherein the evaluation logic can
selectively connect the current source through the impedance
element to the sensor by: opening the first switch; closing the
second switch; closing the third switch; and closing the fourth
switch to detect one or more voltage responses, and based on the
one or more voltage responses, determine a state of operability of
the current source.
14. The printer die of claim 12, wherein the evaluation logic can
selectively connect the current source through the impedance
element to the sensor by: opening the second switch; closing the
fourth switch; closing the third switch; and opening the first
switch, to detect one or more voltage responses and based on the
detected one or more voltage responses, determine a state of
operability of the third switch.
15. The printer die of claim 14, wherein the evaluation logic
simultaneously closes the third switch and opens the first switch
after closing the fourth switch.
Description
BACKGROUND
Fluid ejection dies may be implemented in fluid ejection devices
and/or fluid ejection systems to selectively eject/dispense fluid
drops. Example fluid ejection dies may include nozzles, ejection
chambers and fluid ejectors. In some examples, the fluid ejectors
may eject fluid drops from an ejection chamber out of the
nozzle.
BRIEF DESCRIPTION OF THE DRAWINGS
The disclosure herein is illustrated by way of example, and not by
way of limitation, in the figures of the accompanying drawings in
which like reference numerals refer to similar elements, and in
which:
FIG. 1A illustrates an example fluid ejection system to evaluate a
drive bubble device;
FIG. 1B illustrates an example printer system to evaluate a drive
bubble device;
FIG. 2 illustrates an example cross-sectional view of an example
drive bubble device including a nozzle, a nozzle sensor, and nozzle
sensor control logic;
FIG. 3 illustrates an example circuit that can determine the state
of operability of a DBD (drive bubble device) circuit without the
presence of ink;
FIG. 4 illustrates an example method for determining the state of
operability of a current source of a DBD circuit; and
FIG. 5 illustrates an example method for determining the state of
operability of a control switch of a DBD circuit.
Throughout the drawings, identical reference numbers designate
similar, but not necessarily identical elements. The figures are
not necessarily to scale, and the size of some parts may be
exaggerated to more clearly illustrate the example shown. Moreover
the drawings provide examples and/or implementations consistent
with the description. However, the description is not limited to
the examples and/or implementations provided in the drawings.
DETAILED DESCRIPTION
Examples provide include an evaluation logic for a fluid ejection
system to evaluate a nozzle sensor control logic of the fluid
ejection system's fluid ejection die. The evaluation logic can
include a controller configured to control the states of switches
(e.g. open or close) in order to determine whether the components
of the nozzle sensor control logic are working properly. In some
examples, the nozzle sensor control logic includes DBD (drive
bubble detect) circuitry.
Examples recognize that testing nozzle sensor control logic and an
analog current source of the fluid ejection die at the wafer
functional test level can be beneficial. The only other time
detection of a malfunctioning nozzle sensor control logic and/or
analog current source of the fluid ejection die is when the nozzle
sensor control logic and the analog current source has been built
into a fully functional and ink filled fluid ejection die. Meaning,
the manufacturer can incur significant costs when discovering a
faulty fluid ejection die, if the only defective parts were the
nozzle sensor control logic and/or analog current source. To make
matters more complicated, testing nozzle sensor control logic and
analog current sources of the fluid ejection die without ink can
reveal little or nothing because the response signal can go to
maximum voltage (air has high resistance). Among other benefits,
examples are described that enable a fluid ejection system to
determine the state of operability of the nozzle sensor control
logic at the wafer functional test level.
System Description
FIG. 1A illustrates an example fluid ejection system to evaluate a
drive bubble device. As illustrated in FIG. 1A, fluid ejection
system 100 can include controller 104 and fluid ejection die 106.
Controller 104 can be configured to implement processes and other
logic to manage operations of the fluid ejection system 100. For
example, controller 104 can monitor the circuitry of DBD (drive
bubble detect) 102 in order to determine or evaluate whether DBD
102 is working properly. In some examples, DBD 102 can include
sensor control logic and the sensor control logic can include DBD
circuitry. The DBD circuitry can include control components for the
DBD circuitry. In such examples, DBD 102 can include evaluator 116.
Evaluator 116 can include evaluation logic or circuitry, in which
controller 104 can configure or utilize, to test and monitor the
control components for the DBD circuitry. As such, controller 104
can test and monitor the control components of DBD 102, in order to
determine the state of operability of the control components of DBD
102 (e.g. whether the control components of DBD 102 are working
properly). In other examples, the control components of DBD 102 can
include an analog current source. In some examples, controller 104
can test and monitor the control components of DBD 102 without the
presence of fluid. Meaning controller 104 can test the control
components of DBD 102 at the wafer functional test level, prior to
building the DBD control circuitry into a fully functional and
fluid filled fluid ejection die 106. In some examples, DBD 102 can
include two additional switches so that controller 104 can test the
operability of the control components of DBD 102. In some examples,
controller 104 can include one or more processors to implement the
described operations of fluid ejection-system 100.
In some examples, controller 104 can communicate with fluid
ejection die 106 to fire/eject fluid out of drive bubble device(s)
108. As herein described, any fluid, for example fluid, can be used
can be fired out of drive bubble device(s) 108. In other examples,
controller 104 can transmit instructions 112 to DBD 102 to make
assessments on drive bubble device(s) 108. In other examples,
controller 104 can transmit instructions 112 to fluid ejection die
106 to implement servicing or pumping of drive bubble device(s)
108. In yet other examples, controller 104 can transmit
instructions 112 to DBD 102 to make assessments, and fluid ejection
die 106 to implement servicing of drive bubble device(s) 108 while
DBD 102 is making assessments.
Drive bubble device(s) 108 can include a nozzle, a fluid chamber
and a fluid ejection component. In some examples, the fluid
ejection component can include a heating source. Each drive bubble
device can receive fluid from a fluid reservoir. In some examples,
the fluid reservoir can be ink feed holes or an array of ink feed
holes. In some examples, the fluid can be ink (e.g. latex ink,
synthetic ink or other engineered fluidic inks).
Fluid ejection system 100 can fire fluid from the nozzle of drive
bubble device(s) 108 by forming a bubble in the fluid chamber of
drive bubble device(s) 108. In some examples, the fluid ejection
component can include a heating source. In such examples, fluid
ejection system 100 can form a bubble in the fluid chamber by
heating the fluid in the fluid chamber with the heat source of
drive bubble device(s) 108. The bubble can drive/eject the fluid
out of the nozzle, once the bubble gets large enough. In some
examples, controller 104 can transmit instructions 112 to fluid
ejection die 106 to drive a signal (e.g. power from a power source
or current from the power source) to the heating source in order to
create a bubble in the fluid chamber (e.g. fluid chamber 202). Once
the bubble in the fluid chamber gets big enough, the fluid in the
fluid chamber can be fired/ejected out of the nozzles of drive
bubble device(s) 108.
In some examples, the heating source can include a resistor (e.g. a
thermal resistor) and a power source. In such examples, controller
104 can transmit instructions 112 to fluid ejection die 106 to
drive a signal (e.g. power from a power source or current from the
power source) to the resistor of the heating source. The longer the
signal is applied to the resistor, the hotter the resistor becomes.
As a result of the resistor emitting more heat, the hotter the
fluid gets resulting in the formation of a bubble in the fluid
chamber.
Fluid ejection system 100 can make assessments of drive bubble
device(s) 108 by electrically monitoring drive bubble device(s)
108. Fluid ejection system 100 can electrically monitor drive
bubble device(s) 108 with DBD 102 and a DBD sensing component
operatively communicating with drive bubble device(s) 108. DBD
sensing component can be a conductive plate. In some examples DBD
sensing component can be a tantalum plate. In some examples DBD
sensing component can include a diode. For example, DBD sensing
component can include a thermal sensitive diode.
In some examples, DBD 102 may electrically monitor the impedance of
the fluid in drive bubble device(s) 108 during the formation and
dissipation of the bubble in drive bubble device(s) 108. For
instance, DBD 102 can be operatively connected to a DBD sensing
component that itself is operatively connected to the fluid chamber
of drive bubble device 108. In such a configuration, DBD 102 can
drive a signal or stimulus (e.g. current or voltage) into the DBD
sensing component in order to detect response signals (e.g.
response voltages) of the formation and dissipation of the bubble
in a drive bubble device. If the fluid chamber is empty, the
remaining air has a high impedance, meaning the detected voltage
response would be high. If the fluid chamber had fluid, the
detected voltage response would be low because the fluid at a
completely liquid state has a low impedance. If a steam bubble is
forming in the fluid chamber, while a current is driven into the
DBD sensing component, the detected voltage response would be
higher than if the fluid in the fluid chamber were fully liquid. As
the heating source gets hotter and more fluid vapors are generated,
the voltage response increases because the impedance of the fluid
increases. The detected voltage response would climax when the
fluid from the fluid chamber is ejected from the nozzle. After
which, the bubble dissipates and more fluid is introduced into the
fluid chamber from reservoir.
In some examples, DBD 102 can drive the current (to the DBD sensing
component) at precise times in order to detect one or more voltage
responses, during the formation and dissipation of a bubble in the
fluid chamber. In other examples, DBD 102 can drive a voltage to
the DBD sensing component and monitor the charge transfer or
voltage decay rate, during the formation and dissipation of a
bubble in the fluid chamber 202.
Fluid ejection system 100 can determine the state of operability of
the components of the drive bubble device, based on the
assessments. In some examples, the data of the detected signal
response(s) can be compared with a DBD signal response curve. In
some examples, the signal response(s) are voltage responses. In
other examples, the signal response(s) are the charge transfer or
voltage decay rate. Based on the comparison, fluid ejection system
100 can determine the state of operability of the drive bubble
device being DBD assessed (e.g. whether the components of the drive
bubble device are working properly).
For example, controller 104 can determine the state of operability
of drive bubble device(s) 108, based on data on DBD characteristics
110 transmitted from DBD 102. In some examples, data of DBD
characteristics includes, the data of signal responses transmitted
from DBD 102. Furthermore, controller 104 can compare data of
signal responses to a DBD signal response curve. In some examples,
the DBD signal response curve can include a signal response curve
of a full functioning drive bubble device. If the data of signal
responses is similar to the signal response curve of the full
functioning drive bubble device, then controller 104 can determine
that the DBD assessed drive bubble device 108 is working properly.
On the other hand, if the data of signal responses and the signal
response curve of the full functioning drive bubble device are not
similar, then controller 104 can determine that the DBD assessed
drive bubble device 108 is not working properly. In yet other
examples, controller 104 can compare the data of signal responses
to a signal response curve of a drive bubble device not working
properly. If the data of signal responses and the signal response
curve of the drive bubble device not working properly are similar,
then controller 104 can determine that the DBD assessed drive
bubble device 108 is not working properly.
Fluid ejection die 106 can include columns of drive bubble devices
108. In some examples, fluid ejection die 106 can include a column
of drive bubble devices 108. Making a DBD (drive bubble detect)
assessment of an entire fluid ejection die can take too long and
the later assessed drive bubble devices on the fluid ejection die
may have been idle too long and become too degraded to be able to
undergo assessment. One approach to combat this problem, is by
halting assessment of the entire fluid ejection die to service
(e.g. eject/pump fluid currently in the drive bubble device or
recirculate the fluid currently in the drive bubble device) the
degraded drive bubble device. However such an approach extends the
time for assessment and can even contribute to the degradation of
the drive bubble device to degrade further. In some examples, fluid
ejection system 100 can simultaneously perform an assessment of
drive bubble device 108 and service the remaining drive bubble
devices 108 not undergoing assessment. In other examples, fluid
ejection device 100 can simultaneously perform an assessment of one
drive bubble device 108 of one column of drive bubble devices and
service all drive bubble devices 108 of the remaining columns not
selected for assessment.
In some examples, fluid ejection die system 100 can be a printer
system. FIG. 1B illustrates an example printer system to evaluate a
drive bubble device. As illustrated in FIG. 1B, printer system 150
can include modules/components similar to fluid ejection system
100. For example, DBD 154 can include sensor control logic and the
sensor control logic can include DBD circuitry. The DBD circuitry
can include control components for the DBD circuitry. In some
examples, DBD 154 can include evaluator 164. Evaluator 164 can
include evaluation logic or circuitry, in which controller 152 can
configure or utilize, to test and monitor the control components
for the DBD circuitry. As such, controller 152 can test and monitor
the control components of DBD 154, in order to determine the state
of operability of the control components of DBD 154 (e.g. whether
the control components of DBD 154 are working properly).
In other examples, controller 152 can evaluate the health and
functionality of fluid ejection die 156 by controller 152 making
assessments on drive bubble device(s) 158. Furthermore, while
controller 152 is making assessments on drive bubble device(s) 158,
controller 152 can instruct fluid ejection die 156 to concurrently
implement servicing or pumping of other drive bubble device(s)
158.
FIG. 2 illustrates an example cross-sectional view of an example
drive bubble device including a nozzle, a nozzle sensor, and nozzle
sensor control logic. As illustrated in FIG. 2, drive bubble device
220 includes nozzle 200, ejection chamber 202, and fluid ejector
212. In some examples, as illustrated in FIG. 2, fluid ejector 212
may be disposed proximate to ejection chamber 202.
Drive bubble device 220 can also include a DBD sensing component
210 operatively coupled to and located below fluid chamber 202. DBD
sensing component can be a conductive plate. In some examples DBD
sensing component 210 is a tantalum plate. As illustrated in FIG.
2, DBD sensing component 210 can be isolated from fluid ejector 212
by insulating layer 218.
In some examples, a fluid ejection die, such as the example of FIG.
1A, may eject drops of fluid from ejection chamber 202 through a
nozzle orifice or bore of the nozzle 200 by fluid ejector 212.
Examples of fluid ejector 212 include a thermal resistor based
actuator, a piezo-electric membrane based actuator, an
electrostatic membrane actuator, magnetostrictive drive actuator,
and/or other such devices.
In examples in which fluid ejector 212 may comprise a thermal
resistor based actuator, a controller can instruct the fluid
ejection die to drive a signal (e.g. power from a power source or
current from the power source) to electrically actuate fluid
ejector 212. In such examples, the electrical actuation of fluid
ejector 212 can cause formation of a vapor bubble in fluid
proximate to fluid ejector 212 (e.g. ejection chamber 202). As the
vapor bubble expands, a drop of fluid may be displaced in ejection
chamber 202 and expelled/ejected/fired through the orifice of
nozzle 200. In this example, after ejection of a fluid drop,
electrical actuation of fluid ejector 212 may cease, such that the
bubble collapses. Collapse of the bubble may draw fluid from fluid
reservoir 204 into ejection chamber 202. In this way, in some
examples, a controller (e.g. controller 104) can control the
formation of bubbles in fluid chamber 202 by time (e.g. longer
signal causes hotter resistor response) or by signal magnitude or
characteristic (e.g. greater current on resistor to generate more
heat).
In examples in which the fluid ejector 212 includes a piezoelectric
membrane, a controller can instruct the fluid ejection die to drive
a signal (e.g. power from a power source or current from the power
source) to electrically actuate fluid ejector 212. In such
examples, the electrical actuation of fluid ejector 212 can cause
deformation of the piezoelectric membrane. As a result, a drop of
fluid may be ejected out of the orifice of nozzle 200 due to the
deformation of the piezoelectric membrane. Returning of the
piezoelectric membrane to a non-actuated state may draw additional
fluid from fluid reservoir 204 into ejection chamber 202.
Examples described herein may further comprise a nozzle sensor or
DBD sensing component 210 disposed proximate ejection chamber 202.
DBD sensing component 210 may sense and/or measure characteristics
associated with the nozzle 200 and/or fluid therein. For example,
the DBD sensing component 210 may be used to sense an impedance
corresponding to the ejection chamber 202. In such examples, the
nozzle sensor 210 may include a first sensing plate and second
sensing plate. In some examples DBD sensing component 210 is a
tantalum plate. As illustrated in FIG. 2, DBD sensing device 210
can be isolated from fluid ejector 212 by insulating layer 218.
Based on the material disposed between the first and second sensing
plates, an impedance may vary. For example, if a vapor bubble is
formed proximate the nozzle sensor 210 (e.g. in fluid chamber 202),
the impedance may differ as compared to when fluid is disposed
proximate the nozzle sensor 210 (e.g. in fluid chamber 202).
Accordingly, formation of a vapor bubble, and a subsequent collapse
of a vapor bubble may be detected and/or monitored by sensing an
impedance with the DBD sensing component 210.
A fluid ejection system can make assessments of drive bubble device
220 and determine a state of operability of the components of drive
bubble device 220 (e.g. whether the components of drive bubble
device 220 are working properly). For example, as illustrated in
FIG. 2, nozzle sensor control logic 214 (including current source
216) can be operatively connected to DBD sensing component 210 to
monitor characteristics of the drive bubble device, during the
formation and dissipation of the a bubble in fluid chamber 202. For
instance, some examples, nozzle sensor control logic 214 can be
operatively connected to DBD sensing component 210 to electrically
monitor the impedance of the fluid in fluid chamber 202 during the
formation and dissipation of the bubble in fluid chamber 202.
Nozzle sensor control logic 214 can drive a current from current
source 216 into DBD sensing component 210 to detect a voltage
response from fluid chamber 202 during the formation and
dissipation of a bubble. In some examples, nozzle sensor control
logic 214 can drive the current (to DBD sensing component 210) at
precise times in order to detect one or more voltage responses,
during the formation and dissipation of a bubble in fluid chamber
202. In other examples, nozzle sensor control logic 214 can drive a
voltage to DBD sensing component 210 and monitor the charge
transfer or voltage decay rate, during the formation and
dissipation of a bubble in fluid chamber 202. Nozzle sensor control
logic 214 can transmit data related to the voltage responses to a
controller (e.g. controller 104) of the fluid ejection system (e.g.
fluid ejection system 100). Similar to the principles described
earlier, the controller can then determine the state of operability
of drive bubble device 200, based on the received data. In some
examples, nozzle sensor control logic 214 can include DBD
circuitry. Furthermore, in such examples, the DBD circuitry can
include control components of the DBD circuitry.
In some examples, the fluid ejection system can assess the state of
operability of the control components of nozzle sensor control
logic 214 (e.g. whether the control components of DBD circuit 214
are working properly). For example, nozzle sensor control logic 214
can include two additional switches so that the fluid ejection
system (e.g. controller 104) can test the operability of the
control components of nozzle sensor control logic 214 (including
current source 216). In some examples, the fluid ejection system
can test and monitor the control components of nozzle sensor
control logic 214 without the presence of fluid. Meaning the fluid
ejection system can test the control components of nozzle sensor
control logic 214 at the wafer functional test level, prior to
building nozzle sensor control logic 214 into a fully functional
and fluid filled fluid ejection die.
FIG. 3 illustrates an example circuit that can determine the state
of operability of a DBD circuit without the presence of ink. The
DBD circuit can include switch 306, switch 310, analog current
source 304, and controller 300 (analogous to controller 104).
Controller 300 is operatively connected to switch 306, switch 310
and the analog current source 304. Controller 300 can operatively
control the states of switch 306 and 310 (e.g. open or close). In
some examples, as illustrated by FIG. 3, the DBD circuit can be
operatively connected to DBD sensing component 308.
In some examples, DBD 102 can include evaluator 116. Evaluator 116
can include logic or components that enable controller 104 to test
the operability of the control components of DBD 102. For example,
evaluator 116 can include two additional switches (e.g. JFET or
MOSFET) so that controller 104 can test the operability of the
control components of the DBD 102. As illustrated in FIG. 3, the
DBD circuit can also include an additional two switches (e.g.,
evaluator 116)--switch 316 and switch 318. Controller 300 can be
operatively connected to switch 316 and switch 318 and switch 316
to switch 306 and switch 318. Furthermore controller 300 can
control the states of switch 316 and switch 318 (e.g. open and
close). As shown in FIG. 3, switch 316 is also connected to ground
326. As such controller 300 can test the operability of the control
components of the DBD 102, with the inclusion of switch 316 (to
ground 326) and switch 318. Furthermore, in some examples, the DBD
circuit can also include impedance element 322 to ground 324 that
is connected to switch 310 and 318. In some examples, impedance
element 322 can include a shunt resistor, transistor, diode, or any
combination thereof. In other examples, a capacitance component can
be connected in parallel to impedance element 322.
Fluid ejection system 100 can configure the circuitry of DBD 102
for assessments of drive bubble device(s) 108 or for evaluation.
For example, as illustrated in FIG. 3, when the DBD circuitry is
being used for assessments, controller 300 (similar to controller
104) can close switch 316 in order to force the current from
current source 324 to go to ground. When the fluid ejection system
(e.g. fluid ejection system 100) is evaluating the control
components of the DBD circuitry, controller 300 can to open switch
316.
Fluid ejection system 100 can evaluate the state of operability of
the analog current source of the DBD circuit (e.g. whether the
analog current source is working properly). For example, as
illustrated in FIG. 3, controller 300 (similar to controller 104)
can open switch 316 and close switch 318. In some examples, if
switch 306 is initially closed (e.g. because the DBD circuit was in
assessment mode), then controller 300 can open switch 306 as well.
In some examples, if switch 310 is initially closed (e.g. because
the DBD circuit was in assessment mode), then controller 300 can
open switch 310 as well. In other examples, controller 300 opens
switch 306 and switch 310 before opening switch 316 and closing
switch 318. In yet other examples, controller 300 opens switch 306
before opening switch 316 and closing switch 318, and opens switch
316 after closing switch 318. Based on the configuration, the
current from analog current source 326 can go from switch 318 to
impedance element 322 and then to ground 324. As a result, the
voltage response can be detected through bond pad 312. In some
examples, controller 300 can include logic that instructs
controller 300 to detect the voltage response through bond pad 312
and compare it to a voltage profile of a fully functioning current
source.
In some examples, controller 300 can determine the state of
operability of analog current source 326, based on whether the
detected rise in voltage matches the voltage profile of a fully
functioning current source. Furthermore, if controller 300 can
detect a rise in voltage, then controller 300 can also determine
that switch 316 is working properly as well. In some examples,
controller 300 can store data relating to the voltage profile of a
fully functioning current source. In other examples, controller 104
can receive from a network service data relating to a voltage
profile of a fully functioning current source.
Fluid ejection system 100 can evaluate the state of operability of
the control switch of the DBD circuit (e.g. whether the control
switch is working properly). In some examples, controller 300 can
close switch 306, close switch 310, open switch 316 and open switch
318. In some examples, controller 300 simultaneously closes switch
306 and opens switch 316 simultaneously. In other examples,
controller 306 simultaneously closes switch 306 and opens switch
316 after opening switch 318 and closing switch 310. In yet other
examples, controller 306 opens switch 318 before closing switch
310, and simultaneously closing switch 306 and opening switch 316
after closing switch 310. Based on the configuration, the current
from analog current source 326 can go from switch 306, to switch
310, to impedance element 322 and then to ground 324. As a result,
controller 300 can detect a rise in the voltage response through
bond pad 312 and compare it to a voltage profile of a fully
functioning current source.
In some examples, controller 300 can determine the state of
operability of switch 306 (e.g., the control switch), based on
whether the detected rise in voltage matches the voltage profile of
a fully functioning control switch. If switch 306 is not working
properly (e.g. does not close), then the detected rise in the
voltage response would be higher and the voltage would rise faster
than the voltage profile of a fully functioning control switch
(e.g. the voltage rails due to high impedance (basically the PSU
voltage)). In some examples, controller 300 can store data relating
to the voltage profile of a fully functioning switch 306. In other
examples, controller 104 can receive from a network service data
relating to a voltage profile of a fully functioning switch
306.
Methodology
FIG. 4 illustrates an example method for determining the state of
operability of a current source of a DBD circuit. FIG. 5
illustrates an example method for determining the state of
operability of a control switch of a DBD circuit. In the below
discussions of FIGS. 4 and 5 reference may be made to reference
characters representing like features as shown and described with
respect to FIG. 1A, FIG. 1B, FIG. 2 and/or FIG. 3 for purpose of
illustrating a suitable component for performing a step or sub-step
being described.
With reference to FIG. 4, the fluid ejection system 100 (e.g.
controller 104) can test the operability of an analog current
source of DBD 102 (e.g. whether analog current source 326 is
working properly or not) by transmitting instructions 112 to DBD
102 and evaluator 116 to open a first switch of DBD 102 (400) and
close a second switch of DBD 102 (402). By way of example, the
controller 300 can open switch 316 (e.g., the first switch) and
closing switch 318 (e.g., the second switch). Prior to testing the
operability of the components of the DBD circuit, controller 300
may close switch 316 in order to force the current from current
source 324 to go to ground (e.g. because the DBD circuit was making
Assessments of a drive bubble device). In other examples, if switch
306 (e.g., a third switch) is initially closed, then controller 300
can open switch 306. In some examples, if switch 310 (e.g., a
fourth switch) is initially closed, then controller 300 can open
switch 310 as well. In other examples, controller 300 opens switch
306 and 310, before opening switch 316 and closing switch 318. In
yet other examples, controller 300 opens switch 306 before opening
switch 316 and closing switch 318, and opens switch 316 after
closing switch 318.
Controller 104 can determine the detected response voltage(s) from
DBD 102 (404), based on the switch configuration. For example, as
described above, under the switch configuration, the current from
analog current source 326 can travel from switch 318 to impedance
element 322 and then to ground 324. As a result, controller 300 can
detect a rise in the voltage response through bond pad 312.
Controller 104 can determine the state of operability of the analog
current source of DBD 102 based on the detected response voltage(s)
(408). In some examples, as illustrated in FIG. 3, the controller
(e.g. controller 104 or controller 300) can compare the detected
rise in the voltage response to a voltage profile of a fully
functioning current source. The controller (e.g. controller 104 or
controller 300) can determine whether the analog current source of
the DBD circuit (e.g. analog current source 326) is working
properly based on whether the detected rise in voltage matches the
voltage profile of a fully functioning current source. Furthermore,
if the controller (e.g. controller 104 or controller 300) can
determine a detection of the rise in the voltage response, then the
controller can also determine that the first switch (e.g., switch
316) is working properly as well. In some examples, controller 104
can store data relating to the voltage profile of a fully
functioning current source. In other examples, controller 104 can
receive from a network service data relating to the voltage profile
of a fully functioning current source.
With reference to FIG. 5, fluid ejection system 100 (e.g.
controller 104) can test the operability of a control switch of DBD
102 (e.g. whether switch 306 is working properly or not) by
transmitting instructions 112 to DBD 102 and evaluator 116 to open
a first switch (500), open a second switch (502), close a third
switch (504) and close a fourth switch (506). For example, as
illustrated in FIG. 3, controller 300 (analogous to controller 102)
can close switch 306 (e.g., the third switch), close switch 310
(e.g., the fourth switch), open switch 316 (e.g., the first switch)
and open switch 318 (e.g., the second switch). In some examples,
prior to testing the operability of the components of the DBD
circuit, controller 300 can close switch 316 in order to force the
current from current source 324 to go to ground. In some examples,
controller 300 simultaneously closes switch 306 and opens switch
316 simultaneously. In other examples, controller 306
simultaneously closes switch 306 and opens switch 316 after opening
switch 318 and closing switch 310. In yet other examples,
controller 306 opens switch 318 before closing switch 310, and
simultaneously closing switch 306 and opening switch 316 after
closing switch 310.
Controller 104 can determine the detected response voltage(s) from
DBD 102 (508), based on the switch configuration. In some examples,
under the above described switch configuration, the current from
analog current source 326 can travel from switch 306, to switch
310, to impedance element 322 and then to ground 324. As a result,
controller 300 can detect a rise in the voltage response through
bond pad 312 and compare it to a voltage profile of a fully
functioning current source.
Controller 104 can determine the state of operability of the
control switch of DBD 102 based on the detected response
voltage(s). In some examples, the controller (e.g. controller 104
or controller 300) can determine whether the control switch (e.g.
switch 306) is working properly (e.g. does not close), based on
whether the detected rise in voltage matches the voltage profile of
a fully functioning control switch. If control switch (e.g. switch
306) is not working properly (e.g. does not close), then the
detected rise in the voltage response would be higher and the
voltage would rise faster than the voltage profile of a fully
functioning control switch (e.g., the voltage rails due to high
impedance (basically the PSU voltage)). In some examples,
controller 104 can store data relating to the voltage profile of a
fully functioning control switch. In other examples, controller 104
can receive from a network service data relating to the voltage
profile of a fully functioning current switch.
Although specific examples have been illustrated and described
herein, it will be appreciated by those of ordinary skill in the
art that a variety of alternate and/or equivalent implementations
may be substituted for the specific examples shown and described
without departing from the scope of the present invention. This
application is intended to cover any adaptations or variations of
the specific examples discussed herein. Therefore, it is intended
that this invention be limited only by the claims and the
equivalents thereof.
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